Sonya Shin, M.D. has completed an Infectious Disease fellowship at Brigham and Women's and Massachusetts General Hospitals. She has served as a Clinical Consultant on a multidrug-resistant tuberculosis (MDR-TB) project in Peru since 1996. Drs. Paul Farmer, Edward Nardell, and Michael Hughes will serve as mentors for this study. Dr. Shin plans to develop her skills as an independent clinical investigator, while gaining further formal training in epidemiology and decision analysis research. She ultimately hopes to pursue an independent career in TB clinical trials and program management. Several sites at the Harvard Medical School will provide a research environment for the candidate. Both the Division of Social Justice and Health Inequalities at the Brigham and Women's Hospital and the Harvard School of Public Health, will provide ample environment for the candidate's professional development. Socios en Salud and the Ministry of Health in Lima, Peru will provide additional supervision and resources. MDR-TB remains a global health threat. Use of simple methods to rapidly identify multidrug-resistant tuberculosis strains will likely hasten treatment response. The specific aims of this study are to compare the sensitivity and specificity of two rapid drug susceptibility testing (DST) methods, the Luciferase Reporter Mycobacteriophage (LRM) method and a nitrate-reductase colorimetric (Griess) method, to conventional DST; and 2) to compare time to culture conversion among MDR-TB patients among high-risk cases randomized to receive individualized treatment based on either 1) a novel rapid DST method (Griess or Luciferase), 2) BACTEC or 3) conventional DST. Our hypotheses are that 1) the LRM and Griess methods will provide acceptably sensitive and specific alternatives to conventional drug susceptibility testing; and 2) use of rapid drug susceptibility testing compared with conventional DST to screen subjects at high risk for MDR-TB and guide individualized therapy will shorten time to culture-conversion among MDR-TB cases.